ReasonableCharlie
Beautiful scenery, including Skalkaho Falls. Road is mostly dirt, rough in places, very narrow in places and some people drive like fools along this road, throwing up tons of dust and gravel on you. DO NOT take a camper across this pass.
VanderZyppe
A beautiful trip off the beaten path with a lovely waterfall along the way. Just pray that you don't meet too many on-coming trucks as it is very narrow and steep.
777JimC
This road is exactly what it says it is and that is about 40 miles of back country forest roads all unpaved from Gem mountain to Hamilton. It is closed during the winter and can be a little rough if you don't have 4 wheel drive. Not good to pull large campers 20 feet and over. If you do do it at your own risk. Still a very pretty drive away from the main crowds.
algologist
This road is much like a logging road, but is actually partially paved and gravel, traversing a huge forest with multiple falls along the road, a pass, and many views of the mountainous "inner Montana". It is truly a "jewel" in more ways than one, since it is in the Sapphire Mountains. I prefer to start on the east, coming off I-90 on Highway 1, fueling up in Anaconda, and going west. Drive slow, and watch for critters and big vehicles. Pull over when you can to see the falls, and other jaw-dropping views. A good URL on this is a fishing site:http://www.bigskyfishing.com/scenic-drives/skalkaho-highway.phpThis is a famous "back road" that ends in the Bitteroot Valley, and can in turn take you south to the Lost Trail Pass. I will continuing the tour, if you look me up, with many other locations in the "last best place".